An alleged drug dealer has been arrested in Sydney's south after falling asleep opposite a police station with a bag of drugs lying next to him.

Officers spotted the sleeping man outside a business on Montgomery Street in Kogarah, directly across from the police station, about 11.30am on Sunday.

They also noticed a plastic bag containing a white powder lying on the ground next to him.

A police spokesman said the officers woke the man and searched him, finding a further three bags of white powder, believed to be methylamphetamine, or ice.

They allegedly also found three tablets, believed to be ecstasy, a gold watch and more than $2000 cash.

The man was arrested and taken to St George Police Station, where he was charged with supplying a prohibited drug, two counts of possessing a prohibited drug, two counts of having goods in custody, possessing equipment for administering prohibited drugs, and breaching bail.

He was refused bail to appear in Parramatta Local Court on Monday.